A switched mode power supply (SMPS) converts an input voltage to a regulated output voltage, controlling switching transistors to transfer input power through energy storage elements (for example, an inductor and/or capacitor) to a load, supplying load current at the regulated output voltage. An SMPS regulator includes a controller that drives one or more switching transistors coupled at a switching node to the energy storage element(s). In a common configuration, an SMPS regulator (such as buck, boost, buck-boost) includes a power converter/switcher (controller and switching transistor(s)) coupled to an energy storage inductor at a switch node that is switched to form circuit arrangements to supply inductor current to the load, and to an output capacitor in parallel with the load, switched between charge/discharge cycles to maintain the regulated output voltage, and to supply load current.
In some examples, a power converter includes a high and low side switching transistors connected at the switching node, which are switched according to a pulse width modulated (PWM) duty cycle. When the high side transistor is enabled and the low side transistor is disabled, an inductor current increases. When the high side transistor is disabled and the low side transistor is enabled, the inductor current decreases. The PWM duty cycle at the switch node is controlled to supply inductor current, and to charge and discharge the output capacitor, supplying load current and regulating output voltage (e.g., the duty cycle corresponding to the output voltage). The controller includes high and low side drivers, and driver control circuitry that controls the PWM duty cycle switching of the high and low side switching transistors (at the switch node).